The present invention relates to a method for preventing and treating mastitis, which has the highest incidence among genital diseases in mammals, by administering phytase alone or in admixture with feedstuff. The present invention further relates to a composition that contains phytase for preventing and treating mastitis in mammals.
Mastitis is an inflammation of the lactiferous duct system or mammary gland tissues caused by the invasion and proliferation of bacteria in the udder of a mammal. Once mammals get mastitis, the ability to synthesize milk is damaged by the inflammation. That is, the mammals start to secrete abnormal milk, and number of somatic cells, for example, leukocyte in the milk increases. Also, the mammary gland cells are damaged so that they become atrophied and the connective tissue increases, resulting in decreased lactation. In the dairy industry mastitis is known to stop the lactation, seriously damaging dairy production and management (Shigeru Hara, A Manual of Veterinary Medicine, published by Kodansha Ltd., 1988).
Moreover, an increase in the number of somatic cells due to mastitis decreases the commercial value of milk. Milk containing somatic cells above 500,000 cells/ml is discarded.
No effective method for preventing and treating mastitis has been established because of the difficulties in preventing and treating mastitis by pharmaceuticals or vaccination. Acute mastitis is treated by infusing liquid medicine containing antibiotics as active ingredient into the infected udder, injecting antihistamines or 5% glucose solution into the udder, or intra-arterially injecting antibiotics, such as kanamycin and ampicillin (Shigeru Hara, A Manual of Veterinary Medicine, Kodansha Ltd Publishers, 1988). Dairy cows received these treatments are discharged from milk production because of the problem of residual these medicine, which can significantly decrease dairy productivity. In addition, it was recently reported that oral administration of a pharmaceutical organic zinc preparation, for example zinc methionine sulfate suppressed an increase in the number of somatic cells, one symptom of mastitis (Feedstuffs, 57, 52, p11, 1985). However such administration has also been reported to have no efficacy against mastitis (Feedstuffs, 58, 12, p10, 1986).
Phytase is an enzyme that hydrolyzes phytic acid, an organic phosphorus compound that is difficult to digest, and promotes its absorption. Monogastric animals, such as swine and poultry have no phytase in their digestive tracts, so they cannot digest and absorb phytic acid.
In Japan, phytase has been designated as a feed additive (Japan Scientific Feeds Association, Japanese Standards of Feed Additives, 8th ed., 1996,). In other countries, phytase is widely used in feedstuff for swine and poultry farming. Many reports suggest that the addition of phytase into feedstuff for such animals could cause a significant increase in digestibility not only of phosphorus but also of calcium, zinc, proteins and the like (Proceedings of the 1996 Canadian Society of Animal Science Annual Meeting, Lethbrige, Alberta, Canada, A.W. Jongbloed et. al, 1996; British Journal of Nutrition, 64, 525-540, P. C. Simons et. al, 1990). However, there is no known preventive effect of phytase on mastitis.
On the other hand, since the microorganisms that produce phytase exist in their own ruminoreticulum (Cromwell et. al, J. Anim. Sci. 73, 2000-2008, G. L. 1995), the ruminants are believed to be able to decompose phytic acid themselves and administration of phytase is thought to have no effect on digestibility. Thus, phytase is not added to feedstuff for ruminants such as dairy cows.
The purpose of the present invention is to provide a novel method for preventing and treating mastitis in mammals and a composition for preventing and treating mastitis in order to prevent decrease in milk production due to mastitis in livestock, such as a dairy cow.
The present inventors have now found the administration of phytase can prevent and treat mastitis in mammals as a result of diligent research for solving the abovementioned problems.
The present invention relates to:
(1) A method for preventing and treating mastitis in mammals excluding humans, which comprises administering phytase to the mammals;
(2) The method for preventing and treating mastitis in mammals excluding humans of (1), which comprises administering 50 to 5,000 units of phytase per kg of dry feed matter,
(3) The method for preventing and treating mastitis of (1), wherein the mammal is a cow and the feed is formula feed for dairy cows;
(4) A composition for preventing and treating mastitis in mammals excluding humans, which comprises phytase;
(5) The composition for preventing and treating mastitis in mammals excluding humans of (4), which comprises phytase and formula feed; and
(6) The composition for preventing and treating mastitis in mammals excluding humans of (5), which comprises zinc methionine sulfate.